1. Field of the Invention
This invention relates to a metallic multi-wall baseball or softball bat that is characterized by an increased elasticity and hitting performance by virtue of a textured inner wall that is located in minimum but constant face-to-face contact with an outer wall such that the inner and outer walls of the bat are adapted to flex both independently of and simultaneously with one another.
2. Background Art
Metal bats have long been used to play baseball and softball. In order to increase the power that is generated during a batter""s swing for driving a ball a greater distance, some metal bats have a double walled barrel. That is to say, the barrel area of the bat is formed by inner and outer metal shells that cooperate to maximize the impact force between the bat and the ball.
However, the inner and outer barrel shells of the conventional multi-wall metal bats are typically fixed to one another such that one shell cannot move relative to the other. Consequently, the inner and outer shells do not flex independently of one another in response to a ball striking the barrel, whereby to limit the hitting performance of the bat. More particularly, to generate maximum power using a conventional multi-wall bat, the ball must strike the heart of the sweet spot, typically at the center of the barrel. In cases where the ball strikes the barrel at a location other than the sweet spot, energy will be lost such that the travel of the ball following impact will be reduced. Therefore, such conventional multi-wall metal bats having a limited hitting area have proven to be inefficient whenever the ball is struck off-center.
Examples of multi-wall metal bats having a barrel configuration with inner and outer walls are available by referring to the following United States Patents:
However, it may be appreciated that the inner and outer barrel walls of the conventional multi-wall bats do not flex both independently and simultaneously relative to one another. As a result of their confining configurations, the inner and outer barrel walls of these bats either flex independently (e.g. U.S. Pat. Nos. 5,415,398 and 5,899,823) because of a continuous gap between the walls or simultaneously (e.g. U.S. Pat. Nos. 6,053,828 and 6,159,116) because of a uniformly continuous contact between the walls.
A multi-wall, metal bat is disclosed herein which is of the kind to be used for playing baseball or softball. According to a first embodiment, the bat includes a hollow metallic outer shell having a relatively wide barrel at one end thereof, a relatively narrow handle at the opposite end, and a tapered intermediate portion running between the barrel and the handle. Located inside the hollow outer shell in opposing facing alignment with the barrel is a metallic tubular sleeve insert having a textured exterior surface. A high density elastomeric center core at the end of the tubular sleeve insert is surrounded by and mechanically locked to a ring-like metallic end cap. The textured tubular sleeve insert includes a set of preformed spirals that are formed by swaging and pulling an aluminum tube. The tubular sleeve insert maximizes the strength of the barrel while the set of spirals of the tubular sleeve insert limit the points of contact between the insert and the barrel. By virtue of the foregoing, the tubular sleeve insert and the outer shell are adapted to flex both independently of and simultaneously with one another in response to an impact force created when a ball strikes the bat.
In addition, the tubular sleeve insert will move a limited distance in a forward direction through the hollow outer shell relative to the barrel and towards the end cap, whereby the hitting area of the bat is effectively extended to any location along the barrel. In this regard, a set of spring-like positioning pins fixedly connect the barrel, the end cap and the center core to one another. However, the tubular sleeve insert has a corresponding set of oversized pin holes that receive respective ones of the positioning pins so that the tubular sleeve insert is free to slide through the hollow outer shell relative to the aforementioned connection of the barrel, the end cap and center core. Accordingly, the bat of this invention offers improved elasticity and hitting performance over conventional multi-wall metal bats having inner and outer walls that either are fixedly connected together or separated from one another by a continuous gap.
According to a second embodiment of this invention a multi-wall metal bat is disclosed including an inner shell having a wide barrel at one end thereof, a narrow handle at the opposite end, and a tapered intermediate portion running between the barrel and the handle. The barrel of the inner shell has a textured (e.g. preformed spirals) exterior surface that is surrounded by an outer sleeve. A high density elastomeric center core at the end of the barrel of the inner shell is surrounded by and mechanically locked to a ring-like metallic end cap. The opposite facing textured barrel of the inner shell and the outer sleeve lie in limited contact with one another, whereby the outer sleeve and the inner barrel are adapted to flex both independently of and simultaneously with one another in response to an impact force. The outer sleeve, end cap and elastomeric center core are all connected together by a set of spring-like positioning pins that are received through oversized pin holes in the barrel. Accordingly, the combination of the outer sleeve, end cap and center core are free to slide a limited distance in a forward direction relative to the barrel of the inner shell.